(a) Field of the Invention
The present invention relates to a system and a method of controlling anti-jerk for reducing vibration of an electric vehicle using power of a motor.
(b) Description of the Related Art
As generally known in the art, an electric vehicle is a vehicle which runs using power of a battery, and a hybrid electric vehicle simultaneously uses power of a conventional internal combustion engine and power of a battery. The pure electric vehicle runs by only power of a motor operating by power of a battery. The hybrid electric vehicle runs by efficiently combining power of the internal combustion engine and power of the motor.
For example, as shown in FIG. 1, the hybrid electric vehicle may include an engine 10; a motor 20; an engine clutch 30 controls power between the engine 10 and the motor 20; a transmission 40; a differential gear unit 50; a battery 60; a starting/power generation motor 70 starting the engine 10 or generating power according to an output of the engine 10; and a vehicle wheel 80.
Further, the hybrid electric vehicle may include a hybrid control unit (HCU) 110 controlling an overall operation of the hybrid electric vehicle; a battery control unit (BCU) 120 managing and controlling the battery 60; and a motor control unit (MCU) 200 controlling an operation of the motor 20. The battery controller 120 may refer to a battery management system (BMS).
The foregoing constituent elements of the hybrid electric vehicle are apparent to a person of an ordinary skill in the art, and thus a detailed description thereof is omitted.
The starting/power generation motor 70 may refer to an integrated starter and generator (ISG) or a hybrid starter and generator (HSG) in a field of the vehicle.
The hybrid electric vehicle as described above may run in a running mode including an electric vehicle (EV) mode or a pure electric vehicle mode using only power of the motor 20; a hybrid electric vehicle (HEV) mode using torque of the engine 10 as main power and torque of the motor 20 as auxiliary power; and a regenerative braking (RB) mode recovering brake and inertia energy through power generation of the motor 20 and charging the brake and inertia energy in the battery 60 during running due to brake or inertia of the vehicle.
As described above, the hybrid electric vehicle uses both mechanical energy of the engine and electrical energy of a battery, uses optimal operation regions of the engine and the motor, and recovers the energy of the motor during braking, thereby increasing fuel and energy efficiency.
However, in the hybrid electric vehicle as described above, the automatic transmission is coupled with the engine using the engine clutch instead of a torque converter so a mechanical (passive) damping effect of the torque converter may not be obtained.
In the electric vehicle, since a separate damping means is omitted or the damping means becomes small, during gear-shifting, engaging and disengaging of the accelerator pedal and engine clutch coupling. Furthermore, vibration such as shock and jerk (e.g., sudden rapid motion) as well as vibration of a driving shaft occur.
In other words, in an electric vehicle including the foregoing hybrid electric vehicle, since a damping means disposed between a torque source (e.g., an engine or a motor) and a driving system is omitted or the damping is small, vibration from the torque source or vibration from the exterior may not be attenuated. Accordingly, the electric vehicle may not provide a substantially smooth ride and drivability.
As an example of vibration suppress methods according to the related art, an anti-jerk control method recognizes a deviation (e.g., difference) between a model speed and an actual speed of the motor as vibration, and multiplies the deviation between the two speeds by a predetermined value to calculates a result, and feedbacks the result to suppress the vibration.
However, when extracting vibration component based on the deviation between the model speed and the actual speed of the motor, as shown in FIG. 2, an error may be included in the extracted vibration component. As described above, when the errors are included in the vibration component, even when there is no actual vibration, due to the erroneous determination of vibration, a vibration suppress torque may be applied, so that drivability and ride comfort may decrease.
The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.